MONDAY, Nov. 2, 2015 (HealthDay News) -- Some people with a potentially deadly type of irregular heartbeat may be able to play competitive sports, new guidelines say.

The scientific statement from the American Heart Association and the American College of Cardiology pointed out that recent research indicates the risk of sudden cardiac arrest is lower than previously thought for some athletes with irregular heartbeat caused by long QT syndrome and athletes with long QT syndrome who have implanted pacemakers or defibrillators.

People with long QT syndrome can experience fast and chaotic heartbeats that can be life-threatening.

The new statement applies only to athletes with long QT syndrome who play competitive sports directed by a coach, including baseball, football and basketball. It doesn't apply to people who occasionally play sports for exercise or fun.

Since every patient is different, people with long QT syndrome must get their doctor's approval before participating in competitive sports, according to the statement in the journal Circulation and the Journal of the American College of Cardiology.

Dr. Barry Maron, director of the Hypertrophic Cardiomyopathy Center at the Minneapolis Heart Institute Foundation, co-chaired the committee that wrote the statement. He said it is intended to promote decision-making based on the latest research and the patient's understanding of his risk and the health care provider's clinical judgment.

In a news release from the American Heart Association, Maron said that the recommendations are not mandates and are not intended to make "the general medical (and legal) standard of care applicable to all competitive athletes.

"It should be noted that the guidance for patients with hypertrophic cardiomyopathy has not changed," he added. "We still recommend avoiding intense competitive sports for people who have this condition."

People with hypertrophic cardiomyopathy have abnormally thick heart muscles, increasing their risk for life-threatening irregular heartbeat, especially during intense exercise.

Statement writing group co-chairman Dr. Douglas Zipes said in the news release, "The ultimate incentive is to prevent sudden cardiac death in the young, although it is also important not to unfairly or unnecessarily remove individuals from a healthy athletic lifestyle." Zipes is a professor and director of the cardiology division of the Krannert Institute of Cardiology at the Indiana University School of Medicine in Indianapolis.